You should consider reading "The Vital Question" by Nick Lane. Bill Gates strongly recommended it in one of his Gates' notes. It is an exploration of the central role that energy/metabolism has had in the initial formation and continued evolution of life. A subtext in the book is how biologist have been so fixated on the "information" side of evolution (DNA/RNA) they've overlooked the massive importance of metabolism.
Most intriguingly the book presents an extremely specific and extremely plausible theory for the very beginnings of life. i.e., resolving the questions: Was there a cell before there was metabolism? Or conversely, what is metabolism before there is a cell?